Needle plug cock

ABSTRACT

Needle plug cock with seat made of elastically deformable material such as rubber or elastomers of the same kind, characterized in that the said seat (4) comprises an orifice (4a) having a non-circular cross-section such that under the action of the deformation to which it is subjected by the conical portion (7e) of the needle plug as the said plug engaged further into it, it adapts itself gradually to the circular cross-section of the said portion until it bears against the said portion over its entire periphery.

nited States Patent 1 1 1 1 3,825,224 Remane July 23, 1974 [54] NEEDLEPLUG COCK 2,994,343 8/1961 Banks 251 333 x [75] Inventor: Roger Remane,saime colombe 3,557,833 [/1971 Gllmont 25l/205 X France [73] Assignee:Societe Anonyme: Application Des Primary ExaminerHemy Klinksiek Gal,7Paris, France Attorney, Agent, or FirmAlexander & Dowell [22] Filed:July 5, 1973 21 1. N .1 37 ,517 1 App 0 6 57 ABSTRACT [30] ForeignApplication Priority Data Needle plug cock with seat made of elasticallyde- Oct. 25, 1972 France 72.38344 forrnable material such as rubber orelastomers of the 1 same kind, characterized in that the said seat (4)com- [52] US. Cl 251/205, 137/6253, 138/46 prises an orifice (4a) havinga non-circular cross- [51] Int. Cl. Fl6k 47/00 section such that underthe action of the deformation Field Of Search to which it is subjectedby the conical portion (72) of 25 137/6253, .33; 138/ 3, the needle plugas the said plug engaged further into 46 it, it adapts itself graduallyto the circular crossa section of the said portion until it bearsagainst the [56] References Cited said portion over its entireperiphery.

UNITED STATES PATENTS 1,252,411 1/1918 Dickinson 251/333 X 3 Claims, 5Drawing Figures 1 NEEDLE PLUG COCK DESCRIPTION OF THE INVENTION Thepresent invention relates to cocks in which a mobile closure member isconstituted by a needle valve member or plug adapted to co-operate witha corresponding seat. In conventional cocks of the kind concerned, theneedle plug is conical and is controlled axially by means of ascrewthreading so that by making it rotate in the desired direction itis applied against the seat, which is annular in shape.

Such cocks provide excellent sealing-tightness when closed and the costprice of such cocks is not high. On the other hand, they have thedisadvantage of not allowing easy regulation of the rate of flow inactual practice when the flow is relatively slight at maximum opening.To give one particular example to show what is meant, when these areused for supplying a fuel gas under pressure to the burner of a heateror stove or the like, experience shows that the user can regulate theflame only with considerable difficulty, the control provided being notmuch better than a two-position control. In other words, the angle ofrotation of the plug control handle between the closed position and thatwhich corresponds to the maximum supply for the burner is much too smallto permit convenient regulation.

Of course it is possible to obviate this disadvantage by making thescrewthreading which is provided for the axial displacement of theneedle plug in accordance with its angular displacement very fine, butin addition to the fact that fine screwthreads are expensive to make andbecome worn or deteriorate very quickly, this solution has the resultthat a cock provided for a burner of low consumption has to be turnedthrough a considerable number of revolutions when it is used on anotherhaving a higher rate of consumption.

The present invention aims at obviating these disadvantages andpermitting a needle plug cock to be provided which effects easyregulation of the rate of flow even when the apparatus being controlledhas a very small throughflow.

According to the invention the seat of the cock, made of an elasticallydeformable material such as rubber or elastomer s of the same kind,comprises an orifree of noncircular cross-section such that under theaction of the deformation which the conical portion of the needle plugexerts on it, it adapts itself progressively to the circularcross-section of the said portion until it bears against it over itsentire periphery.

It is possible for example to give the seat a crosssection in the formof a square with the corners pointed or rounded. At the beginning of thepenetration of the needle plug the circular cross-section thereof istangential to the sides of the square and the gas or other fluid canpass freely through the four spaces formed between this section and thecorners of the square shape. As the needle plug enters further, thesides of the square. become rounded and come to bear against anappreciable arc of the section of this needle plug, whereas the surfaceof the four aforesaidspaces continually decreases.

able angle of rotation of the plug and that such an angle permits easygradual regulation of the flow of fluid through the cock, even withrelatively coarse-pitch screwthreads.

The accompanying drawings, given by way of example, will make it easierto understand the invention, the features which it comprises and theadvantage which it can provide:

FIG. 1 is a general view in section of a needle plug cock according tothe invention.

FIG. 2 is an exploded perspective view of the seat of the said cock andthe lower portion of the corresponding needle plug.

FIGS. 3 to 5 are diagrammatic views in perspective showing threesuccessive positions of the needle plug and the seat during theoperation of the cock from its position of full opening.

In FIG. 1, 1 designates the cock body or casing, which is made forexample of metal, and comprises a vertical bore divided into threeportions 2a, 2b, and 2c of decreasing diameter, and a transverse duct 3which starts from the intermediate portion 2b of the aforesaid bore. T osimplify explanations and although this is not obligatory, it can besupposed that the fluid in question, such as for example a fuel gasunder pressure, arrives at the lower end of the portion 2a of thevertical bore and issues through the transverse duct 3. Arranged in theaforesaid'portion 2a is a seat 4 the details of which will be describedhereinafter. This seat, the external form of which is cylindrical at thediameter of the portion 2a, abuts against the intermediate shoulderwhich separates the two portions 2a and 2b, and it is retained inposition by a metal washer'S which itself bears on a split sealing ring6 arranged in a groove of the bore.

The upper portion 20 of the vertical bore of the body 1 is screwthreadedinternally to receive a portion-7a, screwthreaded in correspondingfashion, of a metal needle plug which also comprises in addition to thisportion 7a an upper stem 7b which extends out above the body 1 toreceive a suitable manipulating element and then, below thescrewthreaded portion, a cylindri- Thus an instant arrives when theaforesaid spaces disappear completely, and the seat orifice becomesperfectly circular. The cock is then closed in sealing-tight manner. Itwill be readily appreciated that this gradual deformation of the seatcan correspond to a considercal portion 7c of large diameter formed witha groove in which is arranged a toroidal sealing ring 8, a cylindricalportion 7d of reduced diameter, a frustoconical portion 7e and finally acylindrical end portion 7f of reduced diameter. It will be understoodthat if the stem 7b is given a rotating movement there will be an axialdisplacement of the entire needle plug and more particularly'itsfrustoconical portion 7e will rise or descend relatively to the seat 4.v

The seat 4 is made of an elastically deformable mate rial such as rubberor an equivalent elastomer. It comprises an axial orifice 4a of squarecross-section the side of which is substantially equal to the diameterof the end portion 7f of the needle plug.

Operation is as follows: I a

In the position of full opening of the needle plug (FIGS. 1 and 3) thefrustoconical portion 7e of the plug is entirely disengaged from theorifice 4a of the seat. On the contrary, the cylindrical end portion 7fis still at least partly situtated therein, but since its diameter issubstantially equal to the length of the side of the square to which theorifice is formed, it is in contact at the most with the middle of eachof the sides, thus forming between the needle plug and the said seatfour free spaces 9 (FIG. 3) the crosssection of which is in the form ofan isosceles right-angled triangle with a hy- 3 potenuse curved over anarc of 90. The gas under pressure can flow freely through these spacesto reach the outlet orifice 3 and thus reach, for example, the burner ofa heater which thus operates at full power.

If it is desired to moderate the flame of the heater, the needle plug isturned in the direction corresponding to downward movement. Thefrustoconical portion 7e of the plug then penetrates into the orifice4a, deforming it elastically. The spaces 9 thus decrease incross-section as shown in FIG. 4 and the throughflow of gas decreases toa corresponding extent. Finally, a moment arrives when the diameter ofthe frustoconical portion 7e at the level of the upper face of the seat4 becomes greater than the length of the diagonal of the square outlineof the orifice 4a. The latter is then entirely closed and allthroughflow of gas ceases. (Position shown in FIG.

The reduction in the cross-section of the spaces 9 is extremely gradualso that the user can easily regulate the heater, even if the burner hasa very small rate of flow and if the pitch of the screwthreads 2c and 7ais relatively coarse. Thus it is possible more particularly to providecocks for heaters and similar apparatus wherein a rotation of thecontrol knob makes it possible to change from full running to a stoppedstate with a gradual closing zone extending over 270 or even more.

It should be noted that the cylindrical end portion 7f forms in a way akind of core preventing the seat from being crushed axially and guidingthe deformation of the seat. However, its presence is not indispensableand the needle plug could easily terminate in a cone constituting aprolongation of the portion 7e. It will also be appreciated that theorifice 4a, which is assumed to have parallel faces, could on thecontrary have a downwardly converging shape more or less in the mannerof the frustoconical portion 7e itself. Also, the cross section of thisorifice could comprise any desired noncircular shape, for examplepolygonal, rectangular, elliptical etc.

It should also be understood that the description which has been givenhere was given only by way of example and that it does not in any waylimit the scope of the invention, and it would not consititute adeparture from the invention to replace constructional details describedhere by any other equivalent means.

I claim:

1. Needle plug cock with seat made of elastically deformable materialsuch as rubber or elastomers of the same kind, characterised in that thesaid seat (4) comprises an orifice (4a) having a non-circularcrosssection such that under the action of the deformation to which itis subjected by the conical portion (7e) of the needle plug as the saidplug engages further into it, it adapts itself gradually to the circularcross-section of the said portion until it bears against the saidportion over its entire periphery.

2. Cock according to claim 1, characterised in that the needle plugcomprises a cylindrical end portion (7f) the diameter of whichcorresponds substantially to the smallest transverse dimension of theorifice (4a) of the seat (4).

3. Cook according to claim 1, characterised in that the orifice (4a) ofthe seat (4) has a square shape.

1. Needle plug cock with seat made of elastically deformable materialsuch as rubber or elastomers of the same kind, characterised in that thesaid seat (4) comprises an orifice (4a) having a non-circularcross-section such that under the action of the deformation to which itis subjected by the conical portion (7e) of the needle plug as the saidplug engages further into it, it adapts itself gradually to the circularcross-section of the said portion until it bears against the saidportion over its entire periphery.
 2. Cock according to claim 1,characterised in that the needle plug comprises a cylindrical endportion (7f) the diameter of which corresponds substantially to thesmallest transverse dimension of the orifice (4a) of the seat (4). 3.Cock according to claim 1, characterised in that the orifice (4a) of theseat (4) has a square shape.